I found this place posted in another group: ArtsCow. It'll open in a new window.
When I checked it out they give you 1200 prints! 600 4x6 and 600 5x7. The catch is that you can only use 50 or each size per month and you pay shipping. If you order all 100 shipping is like 10bucks.
Their print prices are unbelievable too: